I had no hope of separating the panel from the frame without damaging the frame since the two parts were rusted pretty badly and the screws holding the panel to the frame were completely beyond salvage. So I had to replace both the panel and the frame. I ended up removing the electrical/electronic connections, removing the panel/frame from the hinge and then replacing it with the new parts. Took about 90 minutes but the hardest part was removing other items from the rusting frame without damaging those parts. It looked like the soap dispenser mechanism was the culprit of the water leak causing the rust. So I'll be replacing that now.

Replaced the oven igniter, following the general instructions on the ApplicancePartsPro.com website. It took me a little while to figure out how to get to the wiring for the igniter, as I had no access panel on the back to get to the wires. In my particular Whirlpool oven (very old model) it turned out that you have to remove the pots/pans drawer under the oven to get to the exposed wiring at the back. Once I figured this out, the rest of the replacement was a snap.

Replaced the igniter element and it worked.
Despite the old igniter was still glowing red hot upon power up and the resistance test also showed that there is still a continuity between the igniter element. Thanks to your online technical support for helping me diagnosed the issue.